[PATCH AUTOSEL 6.10 061/197] wifi: rtw89: avoid reading out of bounds when loading TX power FW elements

[Sasha Levin <sashal@kernel.org>]

From: Zong-Zhe Yang <kevin_yang@realtek.com>

[ Upstream commit ed2e4bb17a4884cf29c3347353d8aabb7265b46c ]

Because the loop-expression will do one more time before getting false from
cond-expression, the original code copied one more entry size beyond valid
region.

Fix it by moving the entry copy to loop-body.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240902015803.20420-1-pkshih@realtek.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/realtek/rtw89/core.h | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/core.h b/drivers/net/wireless/realtek/rtw89/core.h
index 112bdd95fc6ea..504660ee3cba3 100644
--- a/drivers/net/wireless/realtek/rtw89/core.h
+++ b/drivers/net/wireless/realtek/rtw89/core.h
@@ -3888,16 +3888,22 @@ struct rtw89_txpwr_conf {
 	const void *data;
 };
 
+static inline bool rtw89_txpwr_entcpy(void *entry, const void *cursor, u8 size,
+				      const struct rtw89_txpwr_conf *conf)
+{
+	u8 valid_size = min(size, conf->ent_sz);
+
+	memcpy(entry, cursor, valid_size);
+	return true;
+}
+
 #define rtw89_txpwr_conf_valid(conf) (!!(conf)->data)
 
 #define rtw89_for_each_in_txpwr_conf(entry, cursor, conf) \
-	for (typecheck(const void *, cursor), (cursor) = (conf)->data, \
-	     memcpy(&(entry), cursor, \
-		    min_t(u8, sizeof(entry), (conf)->ent_sz)); \
+	for (typecheck(const void *, cursor), (cursor) = (conf)->data; \
 	     (cursor) < (conf)->data + (conf)->num_ents * (conf)->ent_sz; \
-	     (cursor) += (conf)->ent_sz, \
-	     memcpy(&(entry), cursor, \
-		    min_t(u8, sizeof(entry), (conf)->ent_sz)))
+	     (cursor) += (conf)->ent_sz) \
+		if (rtw89_txpwr_entcpy(&(entry), cursor, sizeof(entry), conf))
 
 struct rtw89_txpwr_byrate_data {
 	struct rtw89_txpwr_conf conf;
-- 
2.43.0